1. Field of the Invention
The present invention relates generally to the field of optical scanning, and more particularly, to the use of optical scanning components in a digital panoramic camera.
2. Description of the Prior Art
For innumerable years, many people have endeavored to capture visual images which more accurately depict what the human eye perceives. Since a human eye possessing normal visual acuity has a nominal horizontal field of view (FOV) of approximately 137xc2x0, several methods for producing images which incorporate a horizontal FOV of at least a 100xc2x0, known as panoramas, have been developed. These methods as applied to photography include: (1) segmented panorama; (2) swing lens panorama; (3) conventional panorama; (4) rotational panorama; (5) strip scan panorama, and, most recently; (6) virtual reality imagery.
Segmented panorama is the oldest method of creating a photographic image with a wide FOV. This method includes photographing a series of images with a standard camera so that each successive image includes a portion of the previous image. The photographs are then displayed adjacent one another, thereby forming a composite, wide FOV image.
Swing lens panorama, in contrast, is created by utilizing a device which incorporates a camera with a pivoting lens and a film which is fixedly mounted upon a curved plate. The lens pivots from side to side while transferring or xe2x80x9cwipingxe2x80x9d an image onto the fixed film, thereby typically creating a panoramic image with an FOV of approximately 140xc2x0. Numerous contemporary cameras, such as the Widelux 1500, the Noblex 6/150S, the ArtPanorama 170, the Linhof 617, and the Fuji Gx617 Pro, incorporate the swing lens methodology.
Conventional panorama, currently the most common method used to create a panoramic image utilizes a device which incorporates a fixed lens camera and a fixed film. The device records an image which is cropped into an elongated format, thereby rendering an image with a relatively limited FOV.
Unlike conventional panorama, rotational panorama is created by a device which incorporates rotating film and a rotating camera with the film and the camera rotating in opposite directions. These devices are capable of producing panoramas with an FOV of greater than 360xc2x0. Contemporary cameras, such as the Roundshot 35, the LarScan, the Hulcherama 120S, and the Globuscope, incorporate the rotational panorama methodology.
Strip scan panorama, like rotational panorama, is created by a device which incorporates a rotating camera. Unlike rotational panorama, however, film speed of the strip scan device is matched to the speed of a moving image. Images such as finish line photos of races are often taken with this technique.
In contrast to the aforementioned techniques for creating panoramic images, virtual reality (VR) technology allows a person to interact with wide FOV spatial environments through the use of a computer. These environments have heretofore typically been artistic renderings or computer models, which, until recently, required the use of specialized hardware or accessories, such as high-end graphics workstations, 3D goggles, etc. Improvements, particularly in the area of computer software, i.e. Quick Time VR (QTVR) by Apple, among others, allows a person to create interactive panoramic images within a virtual reality environment, thereby allowing a person to interact with wide FOV imagery using only a personal computer.
QTVR allows extremely high quality, photographed or rendered 3D environments or objects to be played back in real-time on low-end computers. QTVR technology allows computer users easily to create and view either a panorama from a perspective of 360xc2x0 or more, or an object from all sides, and is particularly useful in generating imagery for such fields as travel, education, architecture, sales, manufacturing, real estate and art. It should be noted that although QuickTime VR is mentioned throughout for ease of description, there are numerous VR imaging software authoring packages available for various computer operating systems which are well suited for use with the present invention.
Typically, the first step in creating a VR panorama is to take a series of photographs with a standard camera. The camera is rotated after each picture is taken until 360xc2x0 of images along a horizontal plane are captured, allowing some overlap between individual images. Normally 12 to 24 pictures are required depending on the camera lens used. The film containing the images is then processed in a conventional manner.
After the pictures have been processed, the film must be scanned for use on a computer, with the image data being transferred to a computer-readable medium, such as a Kodak PhotoCD (PCD). The images from the PCD must then be loaded into a computer and saved as specific image files.
The next step is sometimes the most time consuming and includes digitally xe2x80x9cstitchingxe2x80x9d together all of the stored digital images. During xe2x80x9cstitchingxe2x80x9d, the QuickTime VR software blends the individual source images into a seamless panorama; however, the stitching process does not always work perfectly. Many times an individual image will be offset or misaligned from an adjacent image which is being imported into the QuickTime VR software resulting in an inability of the software to compensate adequately for the misaligned images. In the event of such an occurrence, manual fine-tuning of the image stitching process is required. This process can take several hours depending on the user""s experience, computer hardware, and the number of images that need to be stitched. (For a more in-depth discussion of xe2x80x9cstitching,xe2x80x9d see U.S. Pat. No. 5,611,033).
When the images have been successfully stitched together, the digital panoramic image can be edited by means of image editing software such as Adobe Photoshop.
Finally, the digital panoramic image is converted into a playable QTVR scene through the use of the QuickTime VR software so that the viewer is presented in the middle of the digital panoramic image and so that the viewer can freely pan around the image, e.g. look upward/downward and zoom in/out. Individual digital panoramic images can then be linked together so the viewer can xe2x80x9cwalk through,xe2x80x9d view and interact with a series of such images.
Since it is anticipated that digital panoramic images for use in virtual reality applications will be used more extensively as the World Wide Web grows, it is, desirable to provide a device which can reduce production time and cost associated with creating digital panoramic images.
Certain objects, advantages and novel features of the invention will be set forth in part in the description that follows and in part will become apparent to those of ordinary skill in the art upon examination of the following or may be learned with the practice of the invention. The objects and advantages of the invention may also be realized and obtained by means of the instrumentalities and combinations particularly pointed out in the appended claims.
The present invention is generally directed to a panoramic digital camera system and method for obtaining digital images in a three dimensional environment. Specifically, a preferred embodiment of the present invention includes a digital camera containing a lens for focusing light onto a linear charge coupled device (CCD) which produces analog signals in response thereto. Infrared filtering means in the optic path is preferably used for eliminating the adverse effects of infrared energy. Additionally, means for amplifying or attenuating the analog signals is included to xe2x80x9cconditionxe2x80x9d or xe2x80x9ctunexe2x80x9d the signals. Also, a slit is positioned in front of the lens and parallel to the CCD to reduce flare. Once the signals are conditioned, they are converted into digital data through an analog to digital converter. The digital data is then transmitted via a digital interface electronics unit to a computer for image processing.
Advantageously, a preferred embodiment of the digital camera is rotatably mounted to a stepper motor, which, through control circuitry, rotates the camera about a substantially vertical axis at the lens"" front nodal point to provide a full panoramic view about a substantially horizontal plane. A pulse generator is also provided which synchronizes the rotation of the digital camera, acquisition of image lines of data, and image processing software running on the computer.
The present invention can also be viewed in general as providing a method for creating digital panoramic images. The method can be broadly summarized as follows: (1) providing an optic path; (2) filtering light that propagates along the optic path so that light having a wavelength below a predetermined wavelength is substantially prevented from propagating along the optic path; (3) providing a charge coupled device along the optic path which is color responsive to the filtered light so that the charge coupled device generates analog signals corresponding to the color information; (4) rotating the optic path about a rotational axis at a predetermined rate/angle; (5) processing the analog signals generated by the charge coupled device; (6) synchronizing the processing of the analog signals with the rotation of the optic path so that a series of processed digital signals corresponding to the color information is produced, and; (7) converting the digital signals into a digital image.
Inasmuch as the digital camera of the present invention is capable of utilizing existing components from contemporary hand-held optical scanners, the present invention potentially enjoys a significant economic advantage over prior art digital panoramic cameras. In addition, the present invention provides digital quality imaging that is economically competitive with conventional film. Moreover, the present invention produces pictures almost immediately, in contrast to developing and digitizing film, which is both time consuming and expensive.
Additional advantages will become apparent from a consideration of the following description and drawings: